Primary cell



May 20, 1952 J. J. COLEMAN ET Al.

PRIMARY CELL Filed NOV. 20, 1948 TZ M9 CARBON 15 IIIIIIIIl/ IIIIIIIJIlllllllll 'III y. m wm mw wm M M RR .l s MZ MQW w l m cwzaf/ ogm Mn O2i4 Patented May 20, 1952 2,597,453 @MARY CELL Joseph J. Coleman andDemetrios V. Louzos, Freeport, Ill.; as'signors, by. mesne assignments',to Burgess Battery. Company, Freeport, Ill., a corporation of Delaware`@pietrasanta 120, 1948, Serie fla-.6515er t. y y f n aqueouselectrolyte, however, has "dvan thatittends to'atta'ck the negaletrdeWhilethe cell "is not in operation, ult that the `c'selllim'i'ergoespersistent oratin nand ehaustion unless the menis successfully resisted.rLllhe v es "sive deterioration andY eXhaus-L aus'e has been one of thechief con ontiig the prir'nar'y batteryindustendency is inox/Jepronounced with the lily electroneg'ative ihetals, 'such as mag- N 'andthefuseof l'such metals has been y ally avoided `for this reason. Thelatter are natrirally `nuire desirableb'ecaus'e they impart to the ee ahiehfvnage and the ability to 'denver a of electrical "energy but,neverthel s little fuse hasY been nad'e of'them in the usey they areLinr'e*si'ls'ceptible to attack trede than'do v'vater and the aqueouselectrolytes A.

einfployed heretofore. l

It is the bjecto'f the invention to provide lan improved primaryA cellenployng a nnoniaoiueous solvent in the electrolyte in `vvhich cell thenega!- tive electrode suffers only `slight attack Aby the electrolt'eand does not undergo vobjectionalole 'de atentos@ when@ .er am@ IJPatnf. I ll ther object the invention to rnalge 3 Claims. (Cl. 13G-100):metal such as magnesium vfor the negative electro'de; thus providing' acell having 'a'higher voltage and reducing the number of 'celIs requiredin a battery 'of predetermined voltagejandin general, providing abattery capalolefof` delivering 'a high output of electrical energy foritsV size. A'nother 'advantage Yio'vvi'r'ig from the use 'ofvx'naenesiuni iS that vit one `O`if`f the YIlil'e Vtlotlndanli''aridreaqiiy avaiiabie metals. j r

other'obects ane'adyantages win beep-me apparent as thefollovving'description progresses, which ist@ be'ltake'n incnjuriction withmaar,Lcompanyin'g drawingin'whibh the singie gre is a 'sectinal'elevati'n ofafpriniary cell ii'a'c` cordance with the present invention.'

The een comprises' a 'cntinrl u which is gerierally rectan'gylarinshfapefbit 'I'nay' b e 'of `vany desired shape-,arid is open an therep'.1 Thema+ tailler is dipSd 0f Yat'On`` 3'E')`Ildllltil/efnallfel'ial Which is resistant tornoisture andthe electrolyte of theceu, 'suoli as /rbbfhydrchioridey phenol formaldehyde resin, or'th'elike'irv y` Adjacentto the interir surface 'of a Wall 'ot containerYIIl'lis the 'nietal negative electrode YI2 which is inthe 'forni' Ifaat'plat'e vhaving a height SlnW-Hat lvS-sv 'than'.tlt" O the 'ltai'lilIQ. Adjacent'to'the rnefai'iv'eA electrode is" a'lay'fr of bibulousnon-conductive naterial I3, sucl'as blotting paper. The 'bibulo'uslayerI3 absorbs the liquid electrolyte for: the cell. Adjacent tothe bibulouslayer I3 is a 'body of oxidizing pmaterial I4 which Ainay beafconp'axcted liduidahsorb'en't :nass ofhlne'ly id ed particles 'a'niikt're of endu =ive` material, .uh 'as 'mme'. eb black or otherforinoic'a bon, and an' 'oXidiz'i'r'g,T agent which Serves asadepblarz'i f r thist .9611 Said oxidizing agentwill'be describedrnorenfull'y`r hereinafter. The proportions of o dizzying ag n t andconductive materiele* 119i ,-Cal, it f necessary only 'to provideSufflent .of eahi having its upper end portion projectirrr abcve theoxidizing body Ir.v The flsad projecting has a rntal cap fritrfgAfrctiohally thiolj' Said cap ser ng afs one "terminal of the Cell." vTheA. negative 'electrode I2 has a conductor I1 een? nected thereto andserving as the second terminal of the cell. Conductor I1 may be a stripof the same metal as that of which electrode I2 is composed, and may beconnected to the electrode by welding. A sheet of non-conductiveelectrolyteresistant material I8, which may be similar to the materialof which container Ill is composed, is fitted into container I upon thetops of the cell elements. The electrode I5 and terminal I1 projectupwardly through the sheet I8. The top of the cell is sealed by pouringinto the upper portion of the container I0 and upon the sheet I8 amolten sealing composition, such as wax or pitch, which solidiiies uponcooling to form the seal closure I9. The terminals I6 and I1 projectabove the sheet I 8 and the seal I9 and are adapted for connection to anexternal circuit.

A liquid electrolyte is introduced into the container I8 and is absorbedand retained by the bibulous layer I3 and the oxidizing body I4 and isin conductive contact with the negative electrode I2 and the oxidizingbody I4. The electrolyte of the cell is a solution comprising a solventcomponent which is a non-aqueous liquid and a solute component which isa compound which renders the solution conductive and when in thesolution is electrolytically reactive and spontaneously unreactivetoward the negative electrode.

In accordance with the present invention, the solvent which may beemployed is pyridine. This compound is a liquid at ordinary temperaturesand by itself is inert toward the electrodes and the oxidizing agent, i.e., does not appreciably attack or corrode said elements.

Magnesium is employed for the negative electrode I2. Magnesium has theadvantage that it is readily available, stable under most conditions,and produces a relatively high cell voltage.

For the positive electrode I5, a conductive material is chosen which issubstantially inert toward the electrolyte, both in the presence and theabsence of the electrolytic action of the cell. Carbon is suitable andwhere silver chloride is used as the oxidizing agent as describedhereinafter, silver may be used. In the specific cell illustrated, theelectrode I5 is a compressed body ofV carbon similar to that commonlyused in dry cells of the LeClanche type.

For the reactive electrolyte compound, a compound from the groupconsisting of the chloride, nitrate and perchlorate of magnesium isused. Such compound is soluble in the organic solvent and formstherewith an electrolytically conductive solution. Also, when insolution in the solvent it is electrolytically reactive toward thematerial of the negative electrode, but is spontaneously unreactivetoward said electrode, i. e., it is reactive toward the negativeelectrode when the cell electrodes are connected together through anexternal circuit and the cell is operative, and unreactive when theelectrodes are not connected together and the cell is inoperative. Also,it does not cause the plating of metal on the negative electrode. Theamount of reactive compound is not critical, it being only necessary tosupply su'icient thereof to provide the desired reactivity andconductivity. During operation of the cell, the electrolyte enters intoreaction with the negative electrode.

At ordinary temperatures, magnesium chloride and magnesium nitrate existnormally in the form of the hexahydrates MgClaGHzO and Mg(NO3)2.6H2O,and magnesium perchlorate exists in the anhydrous form and also in theform of various hydrates. Such hydrates, as well as the anhydrousmagnesium perchlorate, are suitable in the non-aqueous system of thepresent invention. When the solid hydrate goes into solution in theorganic solvent, it continues to exhibit hydrating power, that is, thepower to bind water, with the result that the water of hydration remainsbound thereto and the organic solvent remains free of water. The dierenthydrates posses hydrating power in varying degrees, and in someinstances a small amount of water may. become dissociated therefrom andexist in freedom in the solvent. Such water will then react with thenegative electrode and cause a slight corrosion of the latter. Suchwater is quickly consumed, however, and does not do objectionabledamage, and the solvent assumes its non-aqueous character. In the sameway, the invention contemplates that a small amount of water maybepresent initially in the electrolyte. This water-is quickly consumed inreacting with the negative electrode and the solvent then assumes itsnon-aqueous character. The solution of the reactive electrolyte compoundin the solvent forms the electrolyte of the cell.

For the oxidizing agent which is included in the oxidizing body I4,manganese dioxide, lead dioxide and silver chloride have been found tobe suitable in accordance with the present invention. The oxidizingagent is one of the factors which determines the potential of thepositive electrode.

The solution which has been described heretofore and which is held bythe oxidizing body I4 and the absorbent layer I3 forms the electrolytefor the cell, providing electrolytic conductivity between the electrodesI2 and I5 and entering readily into electrolytic reaction with thenegative electrode I2 and the oxidizing body I 4, whereby the -cell hasstrong current delivering powers.

A specific example of a satisfactory cell in accordance with theinvention is one having the mechanical construction described heretoforeand composed of elements as follows. The negative electrode is composedof magnesium and the positive electrode is composed of carbon. Thesolvent is pyridine and the reactive electrolyte compound is magnesiumperchlorate, which is present in the pyridine in an amount suflicient toform a saturated solution at 20 C. Such a solution provides satisfactoryreactivity and conductivity. The oxidizing body I4 is a mixture, thesolid components of which comprise approximately by weight vof finelydivided manganese dioxide and approximately 10% of thermal acetyleneblack. The separating member I3 is composed of blotting paper. Such acell has an open circuit voltage of 1.97 volts, and is adapted todeliver current of substantial value.

This application is a continuation-in-part of our application lSerialNo. 713,944, filed December 4, 1946, now abandoned. Primary cells of achar-l acter generally similar to that described herein and employingvarious organic solvents in the electrolyte are disclosed in ourcopending applications Serial Nos. 61,244, 61,245, 61,247 and 61,- 248,all filed November 20, 1948.

What is claimed is:

1. A primary cell comprising a magnesium negative: electrode and apositive electrode, an electrolyte in contact with said electrodescomprising a substantially water-,free pyridine solvent containingmagnesium perchlorate dissolved therein, and an oxidizing body exposedto said electrolyte 5 and in conductive contact with said positiveelectrede.

2. A primary cell comprising positive and negative electrodes composedof carbon and magnesium respectively, an electrolyte in contact withsaid electrodes comprising a substantially Waterfree pyridine solventhaving magnesium perchlorate dissolved therein, and an oxidizing bodycomposed of manganese dioxide exposed to said electrolyte and inconductive contact with said positive electrode.

3. A primary cell comprising a positive electrede and a magnesiumnegative electrode, and an electrolyte in contact with said electrodescomprising a substantially water-free pyridine solvent containingdissolved therein a compound from the group consisting of the chloride,nitrate and perchlorate of magnesium.

JOSEPH J. COLEMAN. DEMETRIOS V. LOUZOS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 660,979 Weymersch Oct. 30, 19001,920,151 Ruben July 25, 1933 2,428,850 Lawson Oct. 14, 1947 FOREIGNPATENTS Number Country Date 391,468 France Aug. 31, 1908

3. A PRIMARY CELL COMPRISING A POSITIVE ELECTRODE AND A MAGNESIUMNEGATIVE ELECTRODE, AND AN ELECTROLYTE IN CONTACT WITH SAID ELECTRODESCOMPRISING A SUBSTANTIALLY WATER-FREE PYRIDINE SOLVENT CONTAININGDISSOLVED THEREIN A COMPOUND FROM THE GROUP CONSISTING OF THE CHLORIDE,NITRATE AND PERCHLORATE OF MAGNESIUM.